Heat oven to 450 degrees. Line 3 baking sheets with parchment. Sift together flour, baking soda, baking powder, salt and sugar. Place 1/4 cup warm water in a small bowl; sprinkle yeast over. Let stand for 5 minutes. Use a pastry cutter to blend the 1/2 pound butter into flour mixture until it resembles coarse meal. Stir in yeast mixture and buttermilk. Turn onto a floured surface and knead until smooth, 2 to 3 minutes. Roll dough to a thickness of 1/4 inch. Cut out 2 1/2 inch rounds. Place 2 inches apart on baking sheet. Knead dough scraps lightly; continue cutting rounds, using all dough. Brush edges with melted butter, fold rounds in half and press edges to seal. Brush tops with butter. Place 2 baking sheets in the oven, leaving the third at room temperature. Bake 6 minutes. rotate baking sheets between oven racks; bake until lightly golden, 5 to 6 minutes more. Bake the third sheet on center rack for 8 to 10 minutes. Serve warm. Posted to MC-Recipe Digest V1 #197 Date: Mon, 12 Aug 1996 22:21:44 -0800 From: Kristine